Light-emitting device and the manufacturing method thereof

ABSTRACT

A light-emitting device includes: a carrier; a light-emitting structure formed on the carrier, wherein the light-emitting structure has a first surface facing the carrier, a second surface opposite to the first surface, and an active layer between the first surface and the second surface; a plurality of first trenches extended from the first surface and passing through the active layer so a plurality of light-emitting units is defined; and a plurality of second trenches extended from the second surface and passing through the active layer of each of the plurality of light-emitting units.

REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.13/225,640 entitled “LIGHT-EMITTING DEVICE AND THE MANUFACTURING METHODTHEREOF”, filed on Sep. 6, 2011, which claims priority from Provisionalapplication Ser. No. 61/380,258 entitled “LIGHT-EMITTING DEVICE”, filedon Sep. 6, 2010, the entire contents of which are incorporated herein byreference.

TECHNICAL FIELD

The application relates to a light-emitting device and the manufacturingmethod thereof.

DESCRIPTION OF BACKGROUND ART

The lighting theory and the structure of the light-emitting diode (LED)is different from that of the conventional lighting source. The LED hasadvantages like a low power loss, a long life-time, no need for warm-uptime, and fast responsive time. Moreover, it is small, shockproof,suitable for mass production, and highly compatible with the demand forthe application requiring a tiny or array-type element, so LEDs arewidely adopted in the market. For example, LEDs can be used in opticaldisplay apparatus, laser diodes, traffic lights, data storage devices,communication devices, illumination devices, medical devices, and so on.

As shown in FIG. 1, a conventional light-emitting array includes: aninsulative sapphire substrate 10; a plurality of light-emitting stacks12 formed on the insulative sapphire substrate 10 and including a p-typesemiconductor layer 121, an active layer 122, and an n-typesemiconductor layer 123. Because the sapphire substrate 10 isinsulative, the light-emitting stacks can be insulated from each otherby forming trenches therebetween with etching processes. Furthermore,after partially etching the plurality of light-emitting stacks 12 to then-type semiconductor layer 123, a first electrode 18 is formed on theexposed area of the n-type semiconductor layer 123, and a secondelectrode 16 is formed on the p-type semiconductor layer 121. Metalwires 19 are then provided to selectively connect the first electrode 18and the second electrode 16 to connect the plurality of light-emittingstacks 12 in parallel or series configuration.

SUMMARY OF THE DISCLOSURE

A light-emitting device includes: a carrier; a light-emitting structureformed on the carrier, wherein the light-emitting structure has a firstsurface facing the carrier, a second surface opposite to the firstsurface, and an active layer between the first surface and the secondsurface; a plurality of first trenches extended from the first surfaceand passing through the active layer so a plurality of light-emittingunits is defined; and a plurality of second trenches extended from thesecond surface and passing through the active layer of each of theplurality of light-emitting units.

A light-emitting device includes: a carrier; a light-emitting structureformed on the carrier, wherein the light-emitting structure has a firstsurface facing the carrier, a second surface opposite to the firstsurface, and an active layer between the first surface and the secondsurface; a plurality of first trenches extended from the first surfaceand passing the active layer so a plurality of light-emitting units isdefined; and a plurality of second trenches extended from the secondsurface of each of the plurality of light-emitting units, wherein eachof the plurality of second trenches partially exposes the bottom of thefirst trench.

A manufacturing method of a light-emitting device includes steps of:providing a substrate; forming a light-emitting structure on thesubstrate, wherein the light-emitting structure comprises a firstsurface and a second surface on the substrate; and defining a pluralityof light-emitting units by forming a plurality of first trenchesextended from the first surface of the light-emitting structure;removing the substrate to expose the second surface; and forming aplurality of second trenches from the second surface.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a cross-sectional view of a conventional light-emittingdevice.

FIGS. 2A to 2H illustrate a first embodiment of a manufacturing methodof a light-emitting element of an embodiment of the present application.

FIG. 3 is a three-dimensional view of a light-emitting element of thefirst embodiment of the present application.

FIG. 4A is a cross-sectional view of a light-emitting element of asecond embodiment of the present application.

FIG. 4B is a three-dimensional view of a light-emitting element of asecond embodiment of the present application.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

FIGS. 2A through 2H illustrate a method of forming a light emittingdiode structure according to a first embodiment of the presentapplication. Referring to FIG. 2A, a substrate 201 is provided. Thematerial of the substrate 201 can be transparent material orelectrically insulating material such as Sapphire, Diamond, Glass,Polymer, Epoxy, Quartz, Acryl, ZnO, or AlN. The substrate 201 can alsobe high reflective materials such as Cu, Al, Mo, Cu—Sn, Cu—Zn, Cu—Cd,Ni—Sn, Ni—Co, Au alloy, or high thermal-dissipative materials such asDiamond Like Carbon (DLC), Graphite, carbon fiber, composite materials,Metal Matrix Composite (MMC), Ceramic Matrix Composite (CMC), PolymerMatrix Composite (PMC), Si, IP, ZnSe, GaAs, SiC, GaP, GaAsP, ZnSe, InP,LiGaO2, or LiAlO2. Then, a first semiconductor layer 202 which is anepitaxy layer of first conductivity, an active layer 204, and a secondsemiconductor layer 206 which is an epitaxy layer of second conductivityare formed on the substrate 201. The first semiconductor layer 202, theactive layer 204 and the second semiconductor layer 206 form alight-emitting structure 208 having an exposed first surface 208 a and asecond surface 208 b directly on the substrate 201. The material of thefirst semiconductor layer 202 and the second semiconductor layer 206comprise indium-containing nitride semiconductor, aluminum-containingnitride semiconductor, or gallium-containing nitride semiconductor. Thematerial of the active layer 204 comprises GaN-based material likeindium gallium nitride, indium gallium aluminum phosphide, aluminumgallium nitride, aluminum gallium arsenide, or indium gallium arsenide.

Referring to FIG. 2B, a patterning process is regionally performed toetch away the second semiconductor layer 206 and the active layer 204until at least the surface of the first semiconductor layer 202 isexposed or partial of the first semiconductor layer 202 is removed, sothe first trench 210 is formed from the surface of the secondsemiconductor layer 206 to the first semiconductor layer 202 to define aplurality of light-emitting units 212. The pattern is formed by themethod such as photolithography, etching, and/or ICP cutting.

Then, covering the surfaces of the second semiconductor layer 206 andthe surfaces of the first trench 210 by depositing an insulating layer214 as shown in FIG. 2C, wherein partial of the surface 202 a of thefirst semiconductor layer 202 and partial of the surface 206 a of thesecond semiconductor layer 206 are exposed. The exposed portions such asthe first connecting portions corresponding to the first semiconductorlayer 202 and the second connecting portions corresponding to the secondsemiconductor layer 206 are used to be the electrical connectionportions later. Besides, the insulating layer 214 is made of thedielectric material such as silicon nitride, silicon oxide, aluminumoxide, or the combination thereof.

Referring to FIG. 2D, a conductive structure 216 is formed on theexposed connecting portions to electrically connect the firstsemiconductor layer 202 of a light-emitting unit 212 and the secondsemiconductor layer 206 of another light-emitting unit 212, wherein thesemiconductor layers are divided into several light emitting diodes inthe following steps and the divided diodes are electrically connected bythe predetermined connecting portions. A contact 217 can be formed onthe second semiconductor layer 206 before forming the conductivestructure 216, and contact the conductive structure 216 to enhance theelectrical conductivity between the conductive structure 216 and thesecond semiconductor layer 206.

Referring to FIG. 2E, the light-emitting structure 208 is bonded to acarrier 218 by an adhesive layer 223. The adhesive layer 223 canadhesively connect the carrier 218 and the light-emitting structure 208.The adhesive layer 223 includes a base portion 223 a attached on thecarrier 218 and a plurality of protrusion portions 223 b correspondingto each of the first trenches 210 in sectional view. In one embodiment,the adhesive layer 223 can be organic insulating material such aspolyimide, BCB, PFCB, Su8, Epoxy, Acrylic Resin, COC, PMMA, PET, PC,Polyetherimide, Fluorocarbon Polymer; in another embodiment, theadhesive layer can be inorganic insulating material such as Silicone,Glass, MgO, Al₂O₃, SiO_(x), TiO₂, SiN_(x), SOG. The adhesive layer 223also can be conductive material such as ITO, InO, SnO, CTO, ATO, AZO,ZTO, ZnO, AlGaAs, GaN, GaP, GaAs, GaAsP, IZO, Ta₂O₅, DLC, Cu, Al, In,Sn, Au, Pt, Zn, Ag, Ti, Ni, Pb, Pd, Ge, Ni, Cr, Cd, Co, Mn, Sb, Bi, Ga,Tl, Po, Ir, Re, Rh, Os, W, Li, Na, K, Be, Mg, Ca, Sr, Ba, Zr, Mo, La,Ag—Ti, Cu—Sn, Cu—Zn, Cu—Cd, Sn—Pb—Sb, Sn—Pb—Zn, Ni—Sn, Ni—Co, or Aualloy and so on. The material of the carrier 218 can be transparentmaterial or electrically insulating material such as Sapphire, Diamond,Glass, Polymer, Epoxy, Quartz, Acryl, ZnO, or AlN. The carrier 218 alsocan be high reflective materials such as Cu, Al, Mo, Cu—Sn, Cu—Zn,Cu—Cd, Ni—Sn, Ni—Co, Au alloy, or high thermal-dissipative materialssuch as Diamond Like Carbon (DLC), Graphite, carbon fiber, compositematerials, Metal Matrix Composite (MMC), Ceramic Matrix Composite (CMC),Polymer Matrix Composite (PMC), Si, IP, ZnSe, GaAs, SiC, GaP, GaAsP,InP, LiGaO₂, or LiAlO₂.

Then, the growth substrate 201 of the light-emitting structure 208 isremoved, as shown in FIG. 2F, by the method such as polishing, laserlift-off, and/or etching.

As shown in FIG. 2G, a second patterning step is performed to divide thelight-emitting structure 208 into several light-emitting units 212 byforming the second trenches 220. The first semiconductor layer 202 andthe active layer 204 are regionally removed to expose the surface of thesecond semiconductor layer 206 or partially remove the secondsemiconductor layer 206. Similarly, the separation step is performed bythe method such as photolithography, etching, and/or ICP cutting. One ofthe second trenches 220 can be formed for the bonding pad formed later.

Finally, as shown in FIG. 2H, similar to the prior steps, the innersidewalls of the second trenches 220 are covered by depositing theinsulating layer 222. Then, a conductive structures 224 are formed inone of the second trenches 220 to form a bonding pad 226 to furtherconnect the second semiconductor layer 206 of one light-emitting unit212 in the light emitting structure 208 to another light-emittingstructure. In addition, if there is no need to connect to anotherlight-emitting structure, the second trenches 220 can be filled up withthe insulating layers 222. Besides, the first bonding pad 226electrically connected to the second semiconductor layer 206 and thesecond bonding pad 227 formed on the first semiconductor layer 202 canalso be formed at the same step or in the different steps while theconductive structures 224 are formed. The first bonding pad 226 can alsobe an extension of the conductive structure 224 and having the samematerial. In another embodiment, the material of the first bonding pad226 can be different from that of the conductive structure 224.

Referring to FIG. 3, the light-emitting device 200 of the firstembodiment including a plurality of light-emitting units 212 divided bythe first trenches 210, the second trenches 220, and a plurality ofthird trenches 230. In the process of dividing the aforesaidlight-emitting structures, the first trenches 210 and the secondtrenches 220 separate the light-emitting structure in a first dimensiond1, and the third trenches 230 separate the light-emitting structure ina second dimension d2 perpendicular to the first dimension. Unlike thefirst trenches 210 and the second trenches 220, the third trenches 230separate the light-emitting structure completely, and the light-emittingdevice 200 has multiple connections respectively connected by thelight-emitting units 212 along the second dimension d2. However, inanother embodiment, the third trenches 230 can be replaced by a trenchstructure similar to that of the first trenches and the second trenches.According to the aforesaid description, the first bonding pads 226 andthe second bonding pad 227 are connected to different polarities ofsemiconductor layers, so the first bonding pad 227 and one of the secondbonding pads 226 can be commonly connected to a power supply (notshown).

Referring to FIG. 4A, a light-emitting device 300 includes: a carrier318; a light-emitting structure 308 formed on the carrier 318, whereinthe light-emitting structure 308 includes a first semiconductor layer302, a second semiconductor layer 306, and an active layer 304 betweenthe first semiconductor layer 302 and the second semiconductor layer306; a plurality of first trenches 310 formed by regionally removing thesecond semiconductor layer 306 and the active layer 304 to expose thefirst semiconductor layer 302; a plurality of second trenches 320 formedby regionally removing the first semiconductor layer 302 to partiallyexpose the bottom of the first trenches 310; a hole 330 formed from oneside of the light-emitting structure 308 and passing the firstsemiconductor layer 302 and the active layer 304. The hole 330 includesan insulating layer 322 on the sidewall thereof, and a conductivestructure 324 can be filled in the hole 330 and contacting the bottom ofthe hole 330, wherein the conductive structure 324 is insulated from thesidewall of the hole 330 by the insulating layer 322. The light-emittingdevice 300 can include a first bonding pad 326 connecting to theconductive structure 324, and a second bonding pad 327 on the firstsemiconductor layer 302 of one of the light-emitting units 312. Thefirst bonding pad 326 and the second bonding pad 327 can be formed atthe same time. The first bonding pad 326 can also be an extension of theconductive structure 324 and having the same material. In anotherembodiment, the material of the first bonding pad 326 can be differentfrom that of the conductive structure 324.

Referring to FIG. 4B, the light-emitting structure 308 are divided intoa plurality of light-emitting units 312 by the first trenches 310 andthe second trenches 320 in dimension 1, and the first trenches 310′ andthe second trenches 320′ in dimension 2. The light-emitting unit 312having the first bonding pads 326 can be used in an AC connection forrectifying, for example, in a Wheatstone-bridge circuit. Thelight-emitting unit 312 having the first bonding pads 326 can representtwo rectification circuits commonly connected to the common circuit ofthe Wheatstone-bridge circuit.

Although the present application has been explained above, it is not thelimitation of the range, the sequence in practice, the material inpractice, or the method in practice. Any modification or decoration forpresent application is not detached from the spirit and the range ofsuch.

What is claimed is:
 1. A light-emitting device comprising: a carrier; alight-emitting structure formed on the carrier, wherein thelight-emitting structure has a first surface facing the carrier, asecond surface opposite to the first surface, and an active layerbetween the first surface and the second surface; a plurality of firsttrenches extended from the first surface and passing through the activelayer so a plurality of light-emitting units is defined; and a pluralityof second trenches extended from the second surface, wherein at leastone of the second trenches comprises an insulating layer on a sidewallthereof.
 2. The light-emitting device according to claim 1, furthercomprising an adhesive layer formed between the plurality oflight-emitting units and the carrier.
 3. The light-emitting deviceaccording to claim 2, wherein the adhesive layer comprises a baseportion attached on the carrier and a plurality of protrusion portionscorresponding to each of the first trenches in a sectional view.
 4. Thelight-emitting device according to claim 2, further comprising aninsulating structure disposed between the adhesive layer and theplurality of light-emitting units.
 5. The light-emitting deviceaccording to claim 4, further comprising a conductive structure disposedbetween the insulating structure and the adhesive layer for electricallyconnecting the plurality of light-emitting units.
 6. The light-emittingdevice according to claim 5, further comprising a contact formed on thefirst surface of the light-emitting unit and connecting to theconductive structure.
 7. The light-emitting device according to claim 6,wherein each of the light-emitting units comprises a first semiconductorlayer between the carrier and one side of the active layer, and a secondsemiconductor layer on the other side of the active layer, and wherein apart of the second trenches extends from the second surface to thesecond semiconductor layer.
 8. The light-emitting device according toclaim 1, further comprising at least a conductive structure formed inthe second trench and contacting a bottom of the second trench.
 9. Thelight-emitting device according to claim 8, wherein the conductivestructure is insulated from a side surface of the light-emitting unit bythe insulating layer.
 10. The light-emitting device according to claim8, wherein the conductive structure formed extends from the secondsurface and passes through the active layer.
 11. The light-emittingdevice according to claim 1, wherein each of the light-emitting unitscomprises a first semiconductor layer between the carrier and one sideof the active layer, and a second semiconductor layer on the other sideof the active layer.